Sierpinski Triangle

#include <graphics.h>

void triunghi(int x1, int y1, int x2, int y2, int x3, int y3)
{
    line(x1,y1,x2,y2);
    line(x1,y1,x3,y3);
    line(x2,y2,x3,y3);
}

void triunghiR(int x1, int y1, int x2, int y2, int x3, int y3)
{
    triunghi((x1+x2)/2,(y1+y2)/2,(x1+x3)/2,(y1+y3)/2,(x2+x3)/2,(y2+y3)/2);
    if (x3-x1>8)
    {
        triunghiR((x1+x2)/2,(y1+y2)/2,x2,y2,(x2+x3)/2,(y2+y3)/2);
        triunghiR(x1,y1,(x1+x2)/2,(y1+y2)/2,(x1+x3)/2,(y1+y3)/2);
        triunghiR((x1+x3)/2,(y1+y3)/2,(x2+x3)/2,(y2+y3)/2,x3,y3);
    }
}

void Sierpinski(int x1, int y1, int x2, int y2, int x3, int y3)
{
    triunghi(x1,y1,x2,y2,x3,y3);
    triunghiR(x1,y1,x2,y2,x3,y3);
}

int main()
{
    initwindow(1200, 1000);

    const int x1=100,x2=getmaxx()-100,x3=getmaxx()/2;
    const int y1=40+(x2-x1)*0.866,y2=y1,y3=40;


    setcolor(14);
    Sierpinski(x1,y1,x2,y2,x3,y3);

    getch();
    cleardevice();
    closegraph();

    return 0;
}